SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '13b75de0e410ef7aa172d777113c5bc51063b0aa8b15074beb2b8182604a96fa' 
  AND token = 'IV9sT0XRPeVxChT3xveMd5x+11vO+fgwRGMOfHkbcv0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}